org.libjpegturbo.turbojpeg

Class TJDecompressor

java.lang.Object

org.libjpegturbo.turbojpeg.TJDecompressor

Direct Known Subclasses:

TJTransformer

public class TJDecompressor
extends Object

TurboJPEG decompressor

Field Summary

Fields

Modifier and Type	Field and Description
private ByteOrder	byteOrder
protected long	handle
protected byte[]	jpegBuf
protected int	jpegBufSize
protected int	jpegHeight
protected int	jpegSubsamp
protected int	jpegWidth
private static String	NO_ASSOC_ERROR

Constructor Summary

Constructors

Constructor and Description
TJDecompressor() Create a TurboJPEG decompresssor instance.
TJDecompressor(byte[] jpegImage) Create a TurboJPEG decompressor instance and associate the JPEG image stored in jpegImage with the newly-created instance.
TJDecompressor(byte[] jpegImage, int imageSize) Create a TurboJPEG decompressor instance and associate the JPEG image of length imageSize bytes stored in jpegImage with the newly-created instance.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Free the native structures associated with this decompressor instance.
void	decompress(BufferedImage dstImage, int flags) Decompress the JPEG source image associated with this decompressor instance and output a decompressed image to the given BufferedImage instance.
private void	decompress(byte[] srcBuf, int size, byte[] dstBuf, int desiredWidth, int pitch, int desiredHeight, int pixelFormat, int flags)
private void	decompress(byte[] srcBuf, int size, int[] dstBuf, int desiredWidth, int pitch, int desiredHeight, int pixelFormat, int flags)
void	decompress(byte[] dstBuf, int desiredWidth, int pitch, int desiredHeight, int pixelFormat, int flags) Decompress the JPEG source image associated with this decompressor instance and output a decompressed image to the given destination buffer.
BufferedImage	decompress(int desiredWidth, int desiredHeight, int bufferedImageType, int flags) Decompress the JPEG source image associated with this decompressor instance and return a BufferedImage instance containing the decompressed image.
byte[]	decompress(int desiredWidth, int pitch, int desiredHeight, int pixelFormat, int flags) Decompress the JPEG source image associated with this decompressor instance and return a buffer containing the decompressed image.
private void	decompressHeader(byte[] srcBuf, int size)
void	decompressToYUV(byte[] dstBuf, int flags) Decompress the JPEG source image associated with this decompressor instance and output a YUV planar image to the given destination buffer.
private void	decompressToYUV(byte[] srcBuf, int size, byte[] dstBuf, int flags)
byte[]	decompressToYUV(int flags) Decompress the JPEG source image associated with this decompressor instance and return a buffer containing a YUV planar image.
private void	destroy()
protected void	finalize()
int	getHeight() Returns the height of the JPEG image associated with this decompressor instance.
byte[]	getJPEGBuf() Returns the JPEG image buffer associated with this decompressor instance.
int	getJPEGSize() Returns the size of the JPEG image (in bytes) associated with this decompressor instance.
int	getScaledHeight(int desiredWidth, int desiredHeight) Returns the height of the largest scaled down image that the TurboJPEG decompressor can generate without exceeding the desired image width and height.
int	getScaledWidth(int desiredWidth, int desiredHeight) Returns the width of the largest scaled down image that the TurboJPEG decompressor can generate without exceeding the desired image width and height.
int	getSubsamp() Returns the level of chrominance subsampling used in the JPEG image associated with this decompressor instance.
int	getWidth() Returns the width of the JPEG image associated with this decompressor instance.
private void	init()
void	setJPEGImage(byte[] jpegImage, int imageSize) Associate the JPEG image of length imageSize bytes stored in jpegImage with this decompressor instance.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

NO_ASSOC_ERROR

private static final String NO_ASSOC_ERROR

See Also:

Constant Field Values

handle

protected long handle

jpegBuf

protected byte[] jpegBuf

jpegBufSize

protected int jpegBufSize

jpegWidth

protected int jpegWidth

jpegHeight

protected int jpegHeight

jpegSubsamp

protected int jpegSubsamp

byteOrder

private ByteOrder byteOrder

Constructor Detail

TJDecompressor

public TJDecompressor()
               throws Exception

Create a TurboJPEG decompresssor instance.

Throws:

Exception

TJDecompressor

public TJDecompressor(byte[] jpegImage)
               throws Exception

Create a TurboJPEG decompressor instance and associate the JPEG image stored in jpegImage with the newly-created instance.

Parameters:

jpegImage - JPEG image buffer (size of the JPEG image is assumed to be the length of the array)

Throws:

Exception

TJDecompressor

public TJDecompressor(byte[] jpegImage,
              int imageSize)
               throws Exception

Create a TurboJPEG decompressor instance and associate the JPEG image of length imageSize bytes stored in jpegImage with the newly-created instance.

Parameters:

jpegImage - JPEG image buffer

imageSize - size of the JPEG image (in bytes)

Throws:

Exception

Method Detail

setJPEGImage

public void setJPEGImage(byte[] jpegImage,
                int imageSize)
                  throws Exception

Associate the JPEG image of length imageSize bytes stored in jpegImage with this decompressor instance. This image will be used as the source image for subsequent decompress operations.

Parameters:

jpegImage - JPEG image buffer

imageSize - size of the JPEG image (in bytes)

Throws:

Exception

getWidth

public int getWidth()
             throws Exception

Returns the width of the JPEG image associated with this decompressor instance.

Returns:

the width of the JPEG image associated with this decompressor instance

Throws:

Exception

getHeight

public int getHeight()
              throws Exception

Returns the height of the JPEG image associated with this decompressor instance.

Returns:

the height of the JPEG image associated with this decompressor instance

Throws:

Exception

getSubsamp

public int getSubsamp()
               throws Exception

Returns the level of chrominance subsampling used in the JPEG image associated with this decompressor instance.

Returns:

the level of chrominance subsampling used in the JPEG image associated with this decompressor instance

Throws:

Exception

getJPEGBuf

public byte[] getJPEGBuf()
                  throws Exception

Returns the JPEG image buffer associated with this decompressor instance.

Returns:

the JPEG image buffer associated with this decompressor instance

Throws:

Exception

getJPEGSize

public int getJPEGSize()
                throws Exception

Returns the size of the JPEG image (in bytes) associated with this decompressor instance.

Returns:

the size of the JPEG image (in bytes) associated with this decompressor instance

Throws:

Exception

getScaledWidth

public int getScaledWidth(int desiredWidth,
                 int desiredHeight)
                   throws Exception

Returns the width of the largest scaled down image that the TurboJPEG decompressor can generate without exceeding the desired image width and height.

Parameters:

desiredWidth - desired width (in pixels) of the decompressed image. Setting this to 0 is the same as setting it to the width of the JPEG image (in other words, the width will not be considered when determining the scaled image size.)

desiredHeight - desired height (in pixels) of the decompressed image. Setting this to 0 is the same as setting it to the height of the JPEG image (in other words, the height will not be considered when determining the scaled image size.)

Returns:

the width of the largest scaled down image that the TurboJPEG decompressor can generate without exceeding the desired image width and height

Throws:

Exception

getScaledHeight

public int getScaledHeight(int desiredWidth,
                  int desiredHeight)
                    throws Exception

Returns the height of the largest scaled down image that the TurboJPEG decompressor can generate without exceeding the desired image width and height.

Parameters:

desiredWidth - desired width (in pixels) of the decompressed image. Setting this to 0 is the same as setting it to the width of the JPEG image (in other words, the width will not be considered when determining the scaled image size.)

desiredHeight - desired height (in pixels) of the decompressed image. Setting this to 0 is the same as setting it to the height of the JPEG image (in other words, the height will not be considered when determining the scaled image size.)

Returns:

the height of the largest scaled down image that the TurboJPEG decompressor can generate without exceeding the desired image width and height

Throws:

Exception

decompress

public void decompress(byte[] dstBuf,
              int desiredWidth,
              int pitch,
              int desiredHeight,
              int pixelFormat,
              int flags)
                throws Exception

Decompress the JPEG source image associated with this decompressor instance and output a decompressed image to the given destination buffer.

Parameters:

dstBuf - buffer that will receive the decompressed image. This buffer should normally be pitch * scaledHeight bytes in size, where scaledHeight can be determined by calling scalingFactor.getScaled(jpegHeight) with one of the scaling factors returned from TJ.getScalingFactors() or by calling getScaledHeight(int, int).

desiredWidth - desired width (in pixels) of the decompressed image. If the desired image dimensions are smaller than the dimensions of the JPEG image being decompressed, then TurboJPEG will use scaling in the JPEG decompressor to generate the largest possible image that will fit within the desired dimensions. Setting this to 0 is the same as setting it to the width of the JPEG image (in other words, the width will not be considered when determining the scaled image size.)

pitch - bytes per line of the destination image. Normally, this should be set to scaledWidth * TJ.pixelSize(pixelFormat) if the decompressed image is unpadded, but you can use this to, for instance, pad each line of the decompressed image to a 4-byte boundary. NOTE: scaledWidth can be determined by calling scalingFactor.getScaled(jpegWidth) or by calling getScaledWidth(int, int). Setting this parameter to 0 is the equivalent of setting it to scaledWidth * TJ.pixelSize(pixelFormat).

desiredHeight - desired height (in pixels) of the decompressed image. If the desired image dimensions are smaller than the dimensions of the JPEG image being decompressed, then TurboJPEG will use scaling in the JPEG decompressor to generate the largest possible image that will fit within the desired dimensions. Setting this to 0 is the same as setting it to the height of the JPEG image (in other words, the height will not be considered when determining the scaled image size.)

pixelFormat - pixel format of the decompressed image (one of TJ.PF_*)

flags - the bitwise OR of one or more of TJ.FLAG_*

Throws:

Exception

decompress

public byte[] decompress(int desiredWidth,
                int pitch,
                int desiredHeight,
                int pixelFormat,
                int flags)
                  throws Exception

Decompress the JPEG source image associated with this decompressor instance and return a buffer containing the decompressed image.

Parameters:

desiredWidth - see decompress(byte[], int, int, int, int, int) for description

pitch - see decompress(byte[], int, int, int, int, int) for description

desiredHeight - see decompress(byte[], int, int, int, int, int) for description

pixelFormat - pixel format of the decompressed image (one of TJ.PF_*)

flags - the bitwise OR of one or more of TJ.FLAG_*

Returns:

a buffer containing the decompressed image

Throws:

Exception

decompressToYUV

public void decompressToYUV(byte[] dstBuf,
                   int flags)
                     throws Exception

Decompress the JPEG source image associated with this decompressor instance and output a YUV planar image to the given destination buffer. This method performs JPEG decompression but leaves out the color conversion step, so a planar YUV image is generated instead of an RGB image. The padding of the planes in this image is the same as the images generated by TJCompressor.encodeYUV(byte[], int). Note that, if the width or height of the image is not an even multiple of the MCU block size (see TJ.getMCUWidth(int) and TJ.getMCUHeight(int)), then an intermediate buffer copy will be performed within TurboJPEG.

Parameters:

dstBuf - buffer that will receive the YUV planar image. Use TJ.bufSizeYUV(int, int, int) to determine the appropriate size for this buffer based on the image width, height, and level of chrominance subsampling.

flags - the bitwise OR of one or more of TJ.FLAG_*

Throws:

Exception

decompressToYUV

public byte[] decompressToYUV(int flags)
                       throws Exception

Decompress the JPEG source image associated with this decompressor instance and return a buffer containing a YUV planar image. See decompressToYUV(byte[], int) for more detail.

Parameters:

flags - the bitwise OR of one or more of TJ.FLAG_*

Returns:

a buffer containing a YUV planar image

Throws:

Exception

decompress

public void decompress(BufferedImage dstImage,
              int flags)
                throws Exception

Decompress the JPEG source image associated with this decompressor instance and output a decompressed image to the given BufferedImage instance.

Parameters:

dstImage - a BufferedImage instance that will receive the decompressed image

flags - the bitwise OR of one or more of TJ.FLAG_*

Throws:

Exception

decompress

public BufferedImage decompress(int desiredWidth,
                       int desiredHeight,
                       int bufferedImageType,
                       int flags)
                         throws Exception

Decompress the JPEG source image associated with this decompressor instance and return a BufferedImage instance containing the decompressed image.

Parameters:

desiredWidth - see decompress(byte[], int, int, int, int, int) for description

desiredHeight - see decompress(byte[], int, int, int, int, int) for description

bufferedImageType - the image type of the newly-created BufferedImage instance (for instance, BufferedImage.TYPE_INT_RGB)

flags - the bitwise OR of one or more of TJ.FLAG_*

Returns:

a BufferedImage instance containing the decompressed image

Throws:

Exception

close

public void close()
           throws Exception

Free the native structures associated with this decompressor instance.

Throws:

Exception

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable

init

private void init()
           throws Exception

Throws:

Exception

destroy

private void destroy()
              throws Exception

Throws:

Exception

decompressHeader

private void decompressHeader(byte[] srcBuf,
                    int size)
                       throws Exception

Throws:

Exception

decompress

private void decompress(byte[] srcBuf,
              int size,
              byte[] dstBuf,
              int desiredWidth,
              int pitch,
              int desiredHeight,
              int pixelFormat,
              int flags)
                 throws Exception

Throws:

Exception

decompress

private void decompress(byte[] srcBuf,
              int size,
              int[] dstBuf,
              int desiredWidth,
              int pitch,
              int desiredHeight,
              int pixelFormat,
              int flags)
                 throws Exception

Throws:

Exception

decompressToYUV

private void decompressToYUV(byte[] srcBuf,
                   int size,
                   byte[] dstBuf,
                   int flags)
                      throws Exception

Throws:

Exception